When to Euthanize A Dog With Osteosarcoma?

When to Euthanize A Dog With Osteosarcoma

Sadly, euthanasia is sometimes a necessary kindness for dogs living with an aggressive tumor like Osteosarcoma. Osteosarcoma is a malignant bone cancer with a high metastasis ability – meaning it spreads to various parts of the body quickly – and the majority of treatment can only slow this spread and reduce pain.

The time to euthanize a dog living with Osteosarcoma is when they simply no longer have a good quality of life. This could mean your dog is no longer able to walk, eat properly, use the bathroom unaided, or they could be in constant pain. The decision to euthanize will always be deeply personal, but it should always consider the vet’s diagnosis, and your dog’s level of suffering.

At every stage of Osteosarcoma, it’s important that you make their life as comfortable as possible and explore the best treatment options you can afford. Certain surgeries and therapies may offer hope and it is always worth seeking out more than one professional opinion to help you make the best decision. Please read through our guide to caring for dogs living with this cancer, their expected lifespan, and more.

Understanding Osteosarcoma in Dogs

Osteosarcoma is an aggressive, painful bone cancer that typically affects large and giant breed dogs.

What is Osteosarcoma?

  • Bone cancer that originates in the skeletal system and destroys normal bone tissue
  • Locally invasive & metastatic – spreads rapidly to lungs & other bones once in the bloodstream
  • Painful – Growing tumors cause severe limb pain
  • Most common primary bone tumor in large/giant breed dogs


While the exact triggers are unknown, these factors can increase a dog’s risk:


Large/giant breeds prone: Great Danes, Irish Wolfhounds, Rottweilers, Saint Bernards

Male dogs are slightly more susceptible than females


Most common between 7-10 years old

Uncommon before age 2 years

Body Size

Heavier dogs are more susceptible

Rapid bone growth periods may increase the risk


No identified genes yet, but likely play a role

If a sibling has osteosarcoma, the risk may increase

Other Factors

Trauma like fractures

Over-supplementing minerals/vitamins could stimulate bone cell proliferation

How Does Osteosarcoma Develops?

The trigger causes normal skeletal cells to transform into malignant cancer cells that rapidly multiply. These cancerous osteoblasts secrete irregular bone tissue that forms a tumor.

  • Tumors destroy healthy bone tissue
  • Weakens structural integrity of bone
  • Causes severe limb pain & lameness

Symptoms of Dog Osteosarcoma

Osteosarcoma can be hard to detect straightaway, but as the tumor develops, your dog will show the following signs:

  • Loss of appetite
  • Seizures
  • Wobbly unbalanced gait
  • Breathing difficulties
  • Noticeable swelling or mass of the affected bone
  • Lethargy
  • Joint pain
  • Reluctance to play

Treatment Options for Osteosarcoma in Dogs

While osteosarcoma cannot be cured, these treatments can prolong life & provide comfort care:


  • Surgically removes limb containing primary tumor
  • Most effective treatment for increasing survival
  • Prevents tumor spread to lungs for the longest time
  • Allows for comfortable, good quality of life

What to Expect with Amputation

  • Surgery time: 2-3 hours
  • Hospitalization: 2-3 days
  • At-home recovery: 10-14 days
  • Staples/sutures removed in 14 days
  • Can use the limb in 6-8 weeks
  • Survival time significantly increased with chemo

Limb-Sparing Surgery

  • Attempts to remove the tumor but the spare limb
  • Outcome highly dependent on location in bone
  • Usually combined with chemo +/- radiation
  • Not appropriate if the tumor extends into the joint
  • Lower success rate than amputation

Palliative Radiation Therapy

  • Shrinks tumors impinging on tissues
  • Reduces pain & inflammation
  • Allows dog to keep limb
  • Given weekly or every 3 weeks
  • Does NOT prevent metastasis


  • Carboplatin or doxorubicin most common
  • Prevents metastases to lungs
  • IV administration every 3 weeks
  • Does not eliminate primary tumor when used alone

What to Expect with Chemo

  • Well tolerated, minimal side effects
  • Appetite loss, nausea, diarrhea possible
  • No hair loss seen
  • Improves survival time significantly

When to Euthanize a Dog with Osteosarcoma?

Quality of Life Decline

  • Decreased appetite/Thirst – If your dog loses interest in food and water despite medication
  • Depression – If your dog withdraws from affection, or activity or seems despondent
  • Difficulty Standing/Walking – Dogs should be able to get up and ambulate fairly normally

Track these metrics daily to notice declines. Create a simple calendar and give each category a daily rating to monitor changes.

If 2 or more decline substantially, speak to your vet about saying goodbye before uncontrolled pain sets in.

Unmanageable Pain

  • Pain that cannot be controlled by medication signals that a dog’s time has come
  • Signs of uncontrolled pain are whimpering, panting, lack of sleep, aggression, restlessness
  • These indicate the cancer has likely metastasized to lungs/other sites

When palliative pain care no longer provides adequate relief, euthanasia spares the dog from further suffering.

Tumor Location Compromises Health

  • Some tumor sites like the upper humerus/femur become fragile over time and prone to fracture
  • A broken leg is intensely painful and difficult to stabilize in elderly dogs
  • Rib/Spinal tumors can make breathing labored or compress nerves

How Long Will a Dog Live with Osteosarcoma?

Each dog’s average survival time will vary depending on the stage of the cancer and the surgeries and therapy options taken. The following details the likely survival rates with each treatment plan:

With Amputation and Chemotherapy (1-2 Years)

Because Osteosarcoma tumors commonly affect the limbs (Appendicular Osteosarcoma) the best course of action to extend your dog’s life is to amputate the affected leg. This removes the primary tumor and alleviates their pain immediately.

Limb-sparing Surgery (1-2 Years)

Depending on the nature of the primary tumor, limb-sparing surgery may be considered which removes the tumor without the need to amputate – extending your dog’s lifespan by a similar time-frame.

There is still a high chance of the cancer spreading via the bloodstream, however, which is why surgery or chemotherapy is often needed to deal immediately with the secondary tumor.

Palliative Radiation and Chemotherapy (6 Months)

If your dog’s initial X-rays reveal that the tumor has already spread (referred to as Extra-skeletal Osteosarcoma that commonly affects the lungs, but also the liver, kidneys and spleen), then this has reached the secondary stage of your dog’s cancer.

At this point, radiation and chemotherapy sessions can only shrink and slow the spread. Your vet will then discuss the likelihood of euthanasia and palliative care measures as the pain becomes too much to bear.

How Long Can a Dog Live with Osteosarcoma without Treatment?

Once a dog has been diagnosed with Osteosarcoma, their average life expectancy without any treatment is approximately two months. This may be shorter or longer depending on when they are diagnosed.

How Fast Does Dog Osteosarcoma Spread?

Very rapidly unfortunately. In 90 to 95 percent of dogs, the tumor will have already metastasized (spread to other body parts) at the time of initial diagnosis of Osteosarcoma.

How Do Dogs Die from Osteosarcoma?

Due to the rapid spread, 80 percent of dogs will die due to lung metastasis, according to a government review of Osteosarcoma treatment. Once the tumor has invaded their airways, dogs will begin to experience severe breathing difficulties, reduced appetite, wheezing, vomiting, lameness and fever.

Is Living with Osteosarcoma Painful?

Osteosarcoma can be very painful for dogs. The symptoms of the most common form of the tumor (Appendicular Osteosarcoma) include a noticeable swelling in the affected limb and lameness. Essentially, the tumor on the bone can be painful enough to make your dog reluctant to play or even walk.

Inform your vet asap if you notice a number of the above symptoms in your dog. They can perform blood work and tissue examinations based on any initial X-ray findings, and if detected early enough, this can help to extend your dog’s life.

Can a Dog Survive Osteosarcoma?

Osteosarcoma is a treatable but incurable disease. Survival odds are based strongly on how early it is detected. Though the rapid spread of the cancer means survival rates are usually poor (with treatment, 50 percent of dogs will survive for a maximum of 1 year), there have been rare stories of hope.

Cost of Dog Osteosarcoma

The costs of treating your dog for Osteosarcoma will vary based on the stage of the tumor’s progression and how well or poorly your dog responds to certain treatments and therapies. Here is an overview of the typical costs:

  • Chemotherapy – Depending on the agent used in chemotherapy, this can cost between $300 and $1,000 per session (one session per week over a cycle of 2 to 6 weeks).
  • Limb amputation – Depending on the extent of surgery required and recovery, limb amputation surgery can cost upward of $500.
  • Radiation therapy – This pain-reducing, tumor-shrinking measure can depend on how far the cancer has progressed and can range between $2,500 and $7,000.

Additional costs to consider are the possibility of a CT scan or the need for intensive care. After-care and comfort measures such as palliative care and considerations for euthanasia will also impact the overall costs.

Can Osteosarcoma in Dogs be Misdiagnosed?

Because the tumor weakens the bone and causes dogs to limp, your dog’s Osteosarcoma could initially be misdiagnosed as an injury or arthritis. This is especially likely if the cancer is detected very early, as the tumor could appear microscopic in an initial x-ray, which is why closely monitoring your dog for the above symptoms is vital.

How Common is Osteosarcoma in Dogs?

Osteosarcoma is unfortunately the most common form of primary bone cancer in dogs and is responsible for over 95 percent of all canine bone tumors. Almost 10,000 dogs are diagnosed with Osteosarcoma each year.

Is Osteosarcoma Hereditary in Dogs?

The risks of developing Osteosarcoma appear to be a mix of genetic and environmental factors. Every dog breed has its own cancer risk genes, and the breeds believed to be predisposed to bone cancer due to their large and long bone formation include:

  • Boxers
  • Great Danes
  • German Shepherds
  • Golden Retrievers
  • Greyhounds
  • Great Pyrenees
  • Irish Setters & Wolfhounds
  • Scottish Deerhounds
  • Saint Bernards
  • Doberman Pinschers

According to research into dog cancer published in a 2007 Genomics journal, 70 percent of the causes of Osteosarcoma in Scottish Deerhounds were “due to heritable traits”. Because body mass is a clear risk factor for Osteosarcoma, many large dog breeds can pass down this paternal imprint into the genes of their offspring.

Can You Prevent Osteosarcoma in Dogs?

While you can’t change your dog’s risk of developing Osteosarcoma (large older male breeds are the riskiest demographic), there are steps owners can take to reduce their dog’s cancer risk:

  • Hold off from spaying/neutering – though the science is still largely inconclusive, some studies have linked this procedure to an increased cancer risk due to the possible alteration of a dog’s hormone levels.
  • Keep them at a healthy weight – canine obesity accounts for up to 30 percent of major cancers, so it’s in your pooch’s best interests to feed them a balanced diet, and keep them on their paws!
  • Avoid exposure to toxins – dogs living in industrial areas or home environments where chemicals and solvents run rampant could be at greater risk of developing certain cancers. Lymphoma tumors, for example, have been diagnosed more commonly in dogs with toxin exposure.

How to Care for a Dog with Osteosarcoma?

In between or after each of the above-mentioned surgical treatments and therapies, caring for your dog should focus on pain management and preserving their quality of life as much as possible.

Palliative treatments such as External Beam Radiation therapy have been offered to control pain in dogs who are refused surgery and have little hope of any extended survival time.

Sadly euthanasia is inevitable in the majority of Osteosarcoma cases. And at this stage, you may want to consider the best form of euthanasia to put your dog at ease, such as an at-home procedure.

This is when your pet is euthanized in their home surroundings so that they feel at ease, and this can be the last great gift you offer them in terms of providing quality of life right to the end – having your beloved pooch experience familiar sights, smells and of course, their family.

What to Feed a Dog with Osteosarcoma?

Most dog foods are made with carbs filled with sugar that help cancer grow. So, to be on the safe side, you’ll want to feed your dog food high in omega-3s to keep the arteries of their walls clear.

The best cancer diet is one that lessens inflammation in your dog and boosts their immune system. Pet Nutritionist Susan Davis recommends the following foods and supplements for dogs living with Osteosarcoma:

  • Curcumin – a natural anti-inflammatory supplement that benefits the skin during radiation therapy and is packed with cancer-fighting nutrients and omega-3 fatty acids.
  • Organic Hemp extract for dogs – ask your vet for this veterinary strength oil for bone cancer that helps to reduce pain and inflammation.
  • Fish and fish oil supplements – the high concentration of omega-3 fatty acids are believed to stall the growth and development of some tumors.
  • Cruciferous veggies – Broccoli and cauliflower have cancer-fighting properties like Folate and Vitamin K.

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